From IGEP - ISEE Wiki
→Setup basics: typo
*libertas: Marvell Libertas 8385/8686/8688 SDIO 802.11b/g card
*firmware: 9.70.3p24 ( download from http://www.marvell.com/support/downloads/search.do ; choose platform Linux 2.6 and download SD-8686-LINUX26-SYSKT-9.70.3.p24-26409.P45-GPL )
This zip archive contains other tarballs ; one of them is named SD-8686-FEDORA26FC6-SYSKT-GPL-9.70.3.p24-26409.P45.tar and contains a FwImage directory. Inside are the two firmware images. You will need to rename helper_sd.bin as sd8686_helper.bin and put both firmware in the lib/firmware (or, as you wish, in lib/firmware/libertas directory of your target root filesystem.
SDIO card should be showed after the image is downloaded to the board.